drm/radeon: Fix eDP for single-display iMac11,2

Apple iMac11,2 (mid 2010) also with Radeon HD-4670 that has the same
issue as iMac10,1 (late 2009) where the internal eDP panel stays dark on
driver load.  This patch treats iMac11,2 the same as iMac10,1,
so the eDP panel stays active.

Additional steps:
Kernel boot parameter radeon.nomodeset=0 required to keep the eDP
panel active.

This patch is an extension of
commit 564d8a2cf3ab ("drm/radeon: Fix eDP for single-display iMac10,1 (v2)")
Link: https://lore.kernel.org/all/lsq.1507553064.833262317@decadent.org.uk/
Signed-off-by: Mark Hawrylak <mark.hawrylak@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index 1471c3a966020af18e87c17808883aee3ec8ad19..4aca09cab4b8cd2ccf63070d9b2296b19fa44e80 100644 (file)
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -2123,11 +2123,12 @@ int radeon_atom_pick_dig_encoder(struct drm_encoder *encoder, int fe_idx)
 
        /*
         * On DCE32 any encoder can drive any block so usually just use crtc id,
-        * but Apple thinks different at least on iMac10,1, so there use linkb,
+        * but Apple thinks different at least on iMac10,1 and iMac11,2, so there use linkb,
         * otherwise the internal eDP panel will stay dark.
         */
        if (ASIC_IS_DCE32(rdev)) {
-               if (dmi_match(DMI_PRODUCT_NAME, "iMac10,1"))
+               if (dmi_match(DMI_PRODUCT_NAME, "iMac10,1") ||
+                   dmi_match(DMI_PRODUCT_NAME, "iMac11,2"))
                        enc_idx = (dig->linkb) ? 1 : 0;
                else
                        enc_idx = radeon_crtc->crtc_id;